1 /*
2 * Copyright 2015 The Netty Project
3 *
4 * The Netty Project licenses this file to you under the Apache License,
5 * version 2.0 (the "License"); you may not use this file except in compliance
6 * with the License. You may obtain a copy of the License at:
7 *
8 * https://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13 * License for the specific language governing permissions and limitations
14 * under the License.
15 */
16 package io.netty.util.internal;
17
18 /**
19 * Provides methods for {@link DefaultPriorityQueue} to maintain internal state. These methods should generally not be
20 * used outside the scope of {@link DefaultPriorityQueue}.
21 */
22 public interface PriorityQueueNode {
23 /**
24 * This should be used to initialize the storage returned by {@link #priorityQueueIndex(DefaultPriorityQueue)}.
25 */
26 int INDEX_NOT_IN_QUEUE = -1;
27
28 /**
29 * Get the last value set by {@link #priorityQueueIndex(DefaultPriorityQueue, int)} for the value corresponding to
30 * {@code queue}.
31 * <p>
32 * Throwing exceptions from this method will result in undefined behavior.
33 */
34 int priorityQueueIndex(DefaultPriorityQueue<?> queue);
35
36 /**
37 * Used by {@link DefaultPriorityQueue} to maintain state for an element in the queue.
38 * <p>
39 * Throwing exceptions from this method will result in undefined behavior.
40 * @param queue The queue for which the index is being set.
41 * @param i The index as used by {@link DefaultPriorityQueue}.
42 */
43 void priorityQueueIndex(DefaultPriorityQueue<?> queue, int i);
44 }